Automatic modules and jpackage

[Mark Raynsford]

On Mon, 2023-11-27 at 16:09 +0000, Mark Raynsford wrote:
> 
> As I mentioned in the blog, I feel like almost all of the
> functionality might already be there (minus a way to get the runtime
> to use -p instead of -cp internally), it's just that there doesn't
> appear to be a way to get jpackage to skip one of the steps that
> causes the failure.
> 

Well, I feel silly.

It turns out that it _is_ possible. The key part is the --runtime-image
option. If there's a normal JDK/JRE image in "jre", and the
application's modules are in "jars", then:

jpackage \
  --runtime-image jre \
  -t app-image \
  --module com.io7m.demo.m3 \
  --module-path jars \
  --name jpackagetest

This will result in an application image where jpackage/lib/app/mods is
a directory containing the untouched application jars. Additionally:

$ cat jpackagetest/lib/app/jpackagetest.cfg
[Application]
app.mainmodule=com.io7m.demo.m3/com.io7m.demo.m3.M3

[JavaOptions]
java-options=-Djpackage.app-version=20231111
java-options=--module-path
java-options=$APPDIR/mods

Running the application shows that it's definitely running in module
path mode.

I've no idea why I spent all day failing to combine the arguments in
this particular way. Maybe my work in 2024 is to submit a documentation
PR that adds this as an example to the jpackage manual page.

-- 
Mark Raynsford | https://www.io7m.com